1. Field of the Invention
This invention relates to free electron lasers and especially to a tunable-frequency, free electron laser.
2. Description of this Prior Art
Previous free electron lasers, i.e., lasers using a beam of relativistic electrons for generating coherent radiation in the centimeter, millimeter, infrared, optical, ultraviolet and X-ray regions of the electromagnetic spectrum, utilize periodic deflection of the transverse periodic magnetic field produced by a linear array of magnets (e.g., see U.S. Pat. No. 3,822,410 granted to J. M. J. Madey on July 2, 1974). The patent shows a laser device which is tunable in frequency by changing the strength, B, of the magnetic field. However, the range of tunability is rather narrow in response to changes in magnetic field strength.